It is the flag of a mouse buttonLeft event

Namespace:  GLSV
Assembly:  GLSV (in GLSV.dll) Version: 1.2009.6.26 (1.2009.06.26)

Syntax

C#
public bool ButtonLeft { get; set; }
Visual Basic (Declaration)
Public Property ButtonLeft As Boolean
Visual C++
public:
property bool ButtonLeft {
	bool get ();
	void set (bool value);
}

See Also